NER: Mesogeochemistry ù Geochemical Reactions and Mass Transfers in Nano-scale Pore Space Confinement

NER：介地球化学 × 纳米级孔隙空间限制中的地球化学反应和传质

• 批准号: 0210820
• 负责人: Huifang Xu
• 金额: $ 9.94万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-15 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0210820&HistoricalAwards=false
• 关键词: NER; Mesogeochemistry; Geochemical; Reactions; Mass

Xu & WangNER-0210820This proposal was received in response to the Nanoscale Science and Engineering initiative NSF 01-157, category NER, and is co-funded by the GEO Directorate.The emergence of nanotechnology has made it possible to manipulate material structures at nanometer scales and has greatly advanced our understanding of how these nano-scale structures give rise to novel physical and chemical properties not seen in bulk materials. Nano-scale pore structures, also called mesoporous structures, are ubiquitous in geologic and engineered materials. Our preliminary studies, both experimentally and theoretically, indicate that chemical reactions in mesopores can be significantly modified, both thermodynamically and kinetically, due to the nano-scale confinement. The objective of this proposal is to (1) clarify the sorption behavior of chemical species in a nano-scale pore space confinement as compared to that in bulk solutions and test the hypothesis that metal sorption on mesopore surface can be greatly enhanced by the confinement effect; and (2) to determine the rates of aqueous species diffusion in nano-scale channels to test the assumption that these channels can provide passages for mass transport during chemical reactions.To isolate the effect of nano-scale pore space confinement, we will conduct parallel sorption experiments on non-mesoporous materials, and the measured sorption capabilities will be compared between mesoporous vs. non-mesoporous materials. Particular attention will be paid to the possible effect of electric double layer (EDL) overlap in mesopores on ion sorption and diffusion. Based on the experimental data, a new surface complexation model will be proposed to explicitly include the effect of EDL overlap. The issues to be addressed in this proposal are fundamental, and the proposed work will highly impact many aspects of geochemical research. The proposed research will establish a theoretical foundation for the development of high-performance functional materials for solving challenging environmental issues we are facing today.

Xu& WangNER-0210820本提案是响应纳米科学与工程倡议NSF 01-157，类别NER，纳米技术的出现使在纳米尺度上操纵材料结构成为可能，并极大地促进了我们对这些纳米材料如何在纳米尺度上被操纵的理解。鳞片结构带来了大块材料中没有的新颖物理和化学性质。 纳米尺度的孔结构，也称为介孔结构，在地质和工程材料中普遍存在。我们的初步研究，实验和理论上，表明中孔中的化学反应可以显着修改，无论是动力学和动力学，由于纳米尺度的限制。 本研究的目的是（1）阐明与本体溶液相比，化学物种在纳米尺度孔隙空间限制中的吸附行为，并验证限制效应可以大大增强金属在介孔表面上的吸附的假设;和（2）测定纳米颗粒中的水相扩散速率，尺度通道，以测试这些通道可以在化学反应期间提供质量传递通道的假设。为了隔离纳米尺度孔隙空间限制的影响，我们将在非介孔材料上进行平行吸附实验，并将测量的吸附能力在中孔与非中孔材料之间进行比较。特别注意的是双电层（EDL）重叠在介孔上的离子吸附和扩散的可能影响。根据实验数据，将提出一种新的表面络合模型，以明确包括EDL重叠的影响。 该提案中要解决的问题是根本性的，拟议的工作将对地球化学研究的许多方面产生重大影响。 这项研究将为开发高性能功能材料以解决我们今天面临的具有挑战性的环境问题奠定理论基础。